Why do homosexuals stereotype heterosexuals?

These days, I feel like almost every blog or Yahoo! Answer that I come across, some members LGBT community seems to be criticizing or stereotyping straight people, you might as well call it hetero-bashing. In fact, it's like being discriminated against (and trust me I've had enough of that in my life, I honestly don't need that from the gay community). Basically, I think some homosexuals paint us heteros as uncaring and awful human beings. I understand that some heteros are this way and couldn't care less, but me, personally, I support the LGBT community. If I had my way, I would to be at every rally, every fight, whenever, wherever, whatever, and I would stand behind the LGBT comm 100%. But nowadays, it's more like a club that I can't have access to. Granted, I am straight and there are certain differences and boundaries, but that shouldn't mean that I can't be there for you. It would be nice if you could give me a chance to have your back. I might not always understand where you're coming from and vice versa, but I could be the shoulder you could cry on if you give me a chance. Open your heart.